The present invention relates generally to apparatus for selectively separating matter between two fluids utilizing semi-permeable membranes, and more particularly, to apparatus in which the membranes have the shape of thin walled tubes through which one of the fluids is intended to flow. Still more particularly, the present invention relates to such an apparatus in which the tubes are surrounded on their outer surface by the other fluid, and in which collective inlets and outlets are provided for the respective fluids.
It has been known in the past to utilize semi-permeable membranes to facilitate the diffusion and/or filtration of matter between two fluids therethrough. For example, such membranes are particularly useful in artificial kidney devices for blood purification, as well as in diafiltration and ultrafiltration devices. From patents such as U.S. Pat. Nos. 3,728,256 and 4,038,190 as well as other patents, it is known to utilize arrangements in which a plurality of tubular semi-permeable membranes are provided in two or more separate chambers connected to one another. In such arrangements, the first fluid passes through the semi-permeable membranes and the second fluid is arranged to pass through the separate chambers around the outer surface of the tubular membranes to selectively separate the matter between the first fluid and the second fluid through the membranes.
The search has, however, continued for improved devices for selective separation of matter between fluids. In particular, the search has continued for such devices which are suitable for mass production while at the same time maintain and/or improve the good flow conditions of the respective fluids which are characteristic of such known devices. Further, the search has continued for devices which improve the effectiveness of the separation of matter between the two fluids.